Page 3054 of 5267

SEAL-OIL PUMP
REMOVAL
1. Remove the transmission from the vehicle (Refer to 21 - TRANSMISSION/AUTOMATIC - 42RLE - REMOVAL).
2. Remove the torque converter from the transmission bellhousing.
3. Use a screw mounted in a slide hammer to remove oil pump seal.
INSTALLATION
1. Clean and inspect oil pump seal seat. Then install seal using Seal Installer C-4193-A.
2. Clean and inspect torque converter hub. If nicks, scratches or hub wear are found, torque converter replacement
will be required.
CAUTION: If the torque converter isbeing replaced, apply a light coating of grease to the crankshaft pilot
hole. Also inspect the engine drive plate for cracks. If any cracks are found replace the drive plate. Do not
attempt to repair a cracked drive plate. Always use new torque converter todrive plate bolts.
3. Apply a light film of transmission oil to the torque converter hub and oilseal lips. Then install torque converter
into transmission. Be sure that the hub lugs mesh with the front pump lugs when installing.
4. Reinstall the transmission into the vehicle. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE -
INSTALLATION)
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SOLENOID-PRESSURE CONTROL
DESCRIPTION
Thepressurecontrolsolenoid(1)ismountedonthe
top of the valve body, next to the line pressure sensor
(2).
The TCM utilizes a closed-loop system to control
transmission line pressure. The system contains a
variable force style solenoid, the Pressure Control
Solenoid. The solenoid is duty cycle controlled by the
TCM to vent the unnecessary line pressure supplied
by the oil pump back to the sump. The system also
contains a variable pressure style sensor, the Line
Pressure Sensor, which is a direct input to the TCM.
The line pressure solenoid monitors the transmission
line pressure and completes the feedback loop to the
TCM. The TCM uses this information to adjust its con-
trol of the pressure control solenoid to achieve the
desired line pressure.
OPERATION
The pressure control solenoid (PCS) is a variable force (VFS) style solenoid. A VFS solenoid is an electro-hydraulic
actuator, combining a solenoid and a regulating valve.
The transmission control module varies the current for the PCS, which variesthepressureinthelinepressure
hydraulic circuit. When the current (duty cycle) of the PCS is low, the pressure in the circuit is higher. At 0 current
(0% duty cycle), the pressure is at the maximum value. Conversely, when thecurrent is maximized (100% duty
cycle), the pressure in the circuit is at the lowest possible value.
REMOVAL
1. Remove the valve body from the transmission.
(Refer to 21 - TRANSMISSION/TRANSAXLE/AU-
TOMATIC - 42RLE/VALVE BODY - REMOVAL)
2. Remove the electrical connectors from the pres-
sure control solenoid (1) and the line pressure sen-
sor (2).
3. Remove the screws (6) holding the pressure con-
trol solenoid (1) and line pressure sensor (2) to the
valve body.
4. Remove the pressure control solenoid and line
pressure sensor from the valve body.
Page 3058 of 5267

SOLENOID
DESCRIPTION
The typical electrical solenoid used in automotive applications is a linear actuator. It is a device that produces
motion in a straight line. This straight line motion can be either forward or backward in direction, and short or long
distance.
A solenoid is an electromechanical device that uses a magnetic force to perform work. It consists of a coil of wire,
wrapped around a magnetic core made from steel or iron, and a spring loaded,movable plunger, which performs
the work, or straight line motion.
The solenoids used in transmission applications are
attached to valves which can be classified asnor-
mally openornormally closed.Thenormally open
solenoid valve is defined as a valve which allows
hydraulic flow when no current or voltage is applied to
the solenoid. Thenormally closedsolenoid valve is
defined as a valve which does not allow hydraulic flow
when no current or voltage is applied to the solenoid.
These valves perform hydraulic control functions for
the transmission and must therefore be durable and
tolerant of dirt particles. For these reasons, the valves
have hardened steel poppets and ball valves. The
solenoids operate the valves directly, which means
that the solenoids must have very high outputs to
close the valves against the sizable flow areas and
line pressures found in current transmissions. Fast
response time is also necessary to ensure accurate
control of the transmission.
The strength of the magnetic field is the primary force
that determines the speed of operation in a particular
solenoid design. A stronger magnetic field will cause
the plunger to move at a greater speed than a weaker
one. There are basically two ways to increase the
force of the magnetic field:
1. Increase the amount of current applied to the
coil or
2. Increase the number of turns of wire in the coil.
The most common practice is to increase the number
of turns by using thin wire that can completely fill the
available space within the solenoid housing. The
strength of the spring and the length of the plunger
also contribute to the response speed possible by a
particular solenoid design.
A solenoid can also be described by the method by
which it is controlled. Some of the possibilities include
variable force, pulse-width modulated, constant ON, or
duty cycle. The variable force and pulse-width modu-
lated versions utilize similar methods to control the
current flow through the solenoid to position the sole-
noid plunger at a desired position somewhere
between full ON and full OFF. The constant ON and
duty cycled versions control the voltage across the
1 - MANUAL VALVE
2 - LINE PRESSURE
3 - 2/4 - LOW REVERSE SOLENOID ENERGIZED
4 - UNDERDRIVE SOLENOID DE-ENERGIZED
5 - UNDERDRIVE CLUTCH
1-OVERDRIVECLUTCH
2 - NO VENT
3 - OVERDRIVE SOLENOID ENERGIZED
4 - MANUAL VALVE
5 - LOW REVERSE/CONVERTER CLUTCH SOLENOID DE-
ENERGIZED
6-SOLENOIDSWITCHVALVE
7 - TAPER
8 - VENT TO SUMP
9 - ORIFICE
10 - CHECK BALL
Page 3059 of 5267
solenoid to allow either full flow or noflow through the solenoid’s valve.
OPERATION
When an electrical current is applied to the solenoid coil, a magnetic field is created which produces an attraction
to the plunger, causing the plunger to move and work against the spring pressure and the load applied by the fluid
the valve is controlling. The plunger is normally directly attached to thevalve which it is to operate. When the cur-
rent is removed from the coil, the attraction is removed and the plunger will return to its original position due to
spring pressure.
The plunger is made of a conductive material and accomplishes this movement by providing a path for the magnetic
field to flow. By keeping the air gap between the plunger and the coil to the minimum necessary to allow free move-
ment of the plunger, the magnetic field is maximized.
Page 3063 of 5267
CONVERTER-TORQUE
DESCRIPTION
The torque converter is a hydraulic device that cou-
ples the engine crankshaft to the transmission. The
torque converter consists of an outer shell with an
internal turbine (1), a stator (4), an overrunning clutch,
an impeller (2) and an electronically applied converter
clutch (6). The converterclutch provides reduced
engine speed and greater fuel economy when
engaged. Clutch engagement also provides reduced
transmission fluid temperatures. The torque converter
hub drives the transmission oil (fluid) pump.
The torque converter is a sealed, welded unit that is
not repairable and is serviced as an assembly.
CAUTION: The torque converter must be replaced
if a transmission failure resulted in large amounts
of metal or fiber contamination in the fluid.
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IMPELLER
The impeller is an integral part of the converter housing. The impeller consists of curved blades placed radially
along the inside of the housing on the transmission side of the converter. As the converter housing is rotated by the
engine, so is the impeller, because they are one and the same and are the driving members of the system.
Impeller
1 - ENGINE FLEXPLATE 4 - ENGINE ROTATION
2 - OIL FLOW FROM IMPELLER SECTION INTO TURBINE
SECTION5 - ENGINE ROTATION
3 - IMPELLER VANES AND COVER ARE INTEGRAL
Page 3065 of 5267
TURBINE
The turbine is the output, or driven, member of the converter. The turbine is mounted within the housing opposite
the impeller, but is not attached to the housing. The input shaft is inserted through the center of the impeller and
splined into the turbine. The design of the turbine is similar to the impeller, except the blades of the turbine are
curved in the opposite direction.
Turbine
1 - TURBINE VANE 4 - PORTION OF TORQUE CONVERTER COVER
2 - ENGINE ROTATION 5 - ENGINE ROTATION
3 - INPUT SHAFT 6 - OIL FLOW WITHIN TURBINE SECTION
Page 3066 of 5267
STATOR
The stator assembly is mounted on a stationary shaft
which is an integral part of the oil pump. The stator (1)
islocatedbetweentheimpeller (2) and the turbine (4)
within the torque converter case.
The stator contains an over-running clutch (1-4), which
allows the stator to rotate only in a clockwise direction.
When the stator is locked against the over-running
clutch, the torque multiplication feature of the torque
converter is operational.